Brake shoe key



Aug. 25, 1936. F. scHAEFl-:R

BRAKE sHoE KEY Filed Nov. 9,l 1955 FIG. 1.

Fla. E.

WITNESJLS "WK /OMLM Patented Aug. 25, k1936 UNiTsD STATES PATENTOFFICE BRAKEoglgls; KEY t t l t I Frederic Schaefer, Pittsburgh,.Pa.

Application November 9, 1935,- Serial No. 49,068Y

9 Claims.

'Ihis invention relates to keys for connecting railway brake shoes to brake heads,v and more particularly to keys of the general construction disclosed in my patent application Serial No. 729,047, filed on June 5, 1934, which has become Patent No. 2,026,324, issued Dec. 31, 1935.

In the key shown in that application an elongate wedge is slidable longitudinally between a pair of arms resiliently biased against it, and the entire key is inserted through the cooperating lugs of a brake head and shoe to connect the shoe to the brake head. Inward movement of the wedge relative to the arms spreads them apart to move a detent on one of the arms into interlocking engagement with one of the cooperating lugs to prevent the key from accidentally coming out of place and releasing the shoe. It has been found that, due to the constant vibrating and stressing of the key in service, there is a tendency for the wedge to work outwardly from its arms-spreading position and to thereby permit the arms to collapse. This loosens the key somewhat and reduces the resiliency or spring tension with which the shoe is held against the head. It has also been found that in driving the wedge into locking position between the arms it sometimes becomes disposed at an angle thereto with its inner end projecting from between the sides of the arms, whereby the arms are not spread far enough apart to securely lock the key in the lugs.

It is among the objects of thisinvention to provide a brake key of the type referred to above which has means for locking the wedge in its arms-spreading position, and means for guiding the wedge while it is being driven longitudinally of the arms to locking position.

The preferred embodiment of the invention is illustrated in the accompanyingA drawing in which Fig. 1 is a side view of the key inserted through the cooperating lugs of a brake head and shoe but not locked therein; Fig. 2 is a View in vertical section showing the key locked in place; Fig. 3 is a face View of the key to reduced scale; Fig. 4 is a similar View of the opposite face thereof; Figs. 5 and 6 are horizontal sections of the key taken on the lines V--V and VI-VI of Fig. 2; and Fig. '7 is a horizontal section taken on the line VII-VII of Fig. 1.

Referring to Fig. 1 of the drawing, a brake shoe l having a central lug 2 is shown associated with a brake head 3 provided with a pair of lugs 4 straddling lug 2. All of these parts are of standard construction. The brake shoe is connected to the brake head by a key comprising a pair of spring arms 6 and 'I connected to each other at their lower ends and spaced apart at their upper ends by a locking strip or wedge 8. The upper ends of the arms are connected together in spaced relation by a metal sleeve 9 engaged at its lower end by an offset I I on arm 'I'. These, or equivalent 5 Y Vforming a stop I2` for engaging the upper end of the brake shoe to limitthe downward movement of the locking key wheninserted in position. The upper. end of armG. is bent outward slightly to form a projection I3 which is adapted to be 15 struck by a hammer 1n driving the key into place. The upper end of wedge 8 isprovided with an eye Ill forming a head for driving thewedge into place and a loop through which a bar can be inserted for pulling or driving the wedge out Vof place. The wedge isalso provided with a detent I5 lwhich projects into offset I I and engages its upper end when the wedge is in its outer position to limit the travel of the wedge and prevent its removal from between the arms of` the key. f

Intermediate of its ends arm 1 is provided with an elongate detent I6 which, in the inserted position of the locking key, preferably lies-just below the lower edge ofthe upper lugvrofv the brakehead. The wedge is provided near its lower end with an offset portion I'I which, when the wedge is in its inner position between the arms as shown in Fig.

2, effectively spreads them outwardly with detent I6 of arm I disposed below the lower edge of upper lug 4. Detent I6 thereby locks the key 35 in the cooperating lugs ofthe brakeV head and shoe and prevents the accidental vremoval of the key therefrom.

When wedge v8- is inits outer position the two arms engage each other for approximately the 40 lower half of their length, as shown in Fig. 1, Vthe upper half of arm 6 being offset relative to its lower part to permit the wedge to be disposed between the upper portions of the arms without spreading the arms apart. Furthermore, arm 'l 45 is provided withan offset portion I8 which receives oiset I1 ofthe wedge when the wedge is` in its outer position soV that .they arms-can lie flat against the wedge, whereby `the key can be inserted in and removed from the lugs without interference from detent I6.

To guide the wedge in its longitudinal movement inwardly between the arms and thereby prevent its lower end from sliding out at an angle and not properly spreading the arms, the Y offset upper half of arm 6 is provided with a longitudinal groove I9 in its inner surface in which there slides a longitudinal rib 2| on the adjoining face of the wedge, as seen in Fig. 5.

As the space through which the wedge passes between the cooperating lugs of the head and shoe varies due to uneven castings and wear of the lugs, whereby it is sometimes quite narrow, the lower end of the wedge is tapered downwardly to permit it to spread the arms even when they are held together by the lugs.

Another feature of this invention is that pro- Vision is made for locking wedge 8 in its inner or arms-spreading position so that it can not work upwardly, due to the constant vibration and flexing to which the key is subject, and allow the arms to collapse. Accordingly, the lower end of the wedge is provided with a plurality of depressions 22 into some of which, when thewedge is in its inner position, project detents 23 and 24 formed on the inner face of arm 6 opposite elongate detent I6 on arm 'l (Fig. 6). The engagement of detents23 and 2e with depressions 22 prevents the wedge from accidentally working out of its arms-spreading position and allowing the arms to collapse, but the wedge can be withdrawn when it is vnecessary to remove the key by striking loop I4 from below or by inserting a bar in the loop and pulling or striking the bar. When the wedge is in its outer position detents 23 and 24 project into the recess formed by detent I6, as shown in Fig. 7, and therefore do not hold the arms apart. Lower detent 24 is preferably larger than upper detent 23 so that when the key-receiving space between the cooperating lugs of the head and shoe is great and the tapered lower end of the wedge is in engagement with lower detent 24, the arms .of the key are spread thereby sufficiently to lock the key in place.

According to the provisions of the patent statutes, I have explained the principle and construction of my invention, and have illustrated and described what I consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A key for connecting a brake shoe to a brake head, comprising a pair of arms connected to each other, a member associated with said arms and movable to and from a position to spread s a'id arms into shoe-locking position, and means for locking said member in its arms-spreading position.

2. A key for connecting a brake shoe to a brake head, comprising a pair of adjacent spring-like arms connected to each other, a member associated with said arms and movable to andfrom a position to spread said arms into shoe-locking position, and means for locking said member in its arms-spreading position, said locking' means being disengaged by positively forcing said member from its arms-spreading position.

3. A key for connecting a brake shoe to a brake head having cooperating lugs, comprising a pair of resilient arms connected to and yieldingly urged towards each other and provided with a lug-engaging detent, and a member slidably mounted between said arms and movable longitudinally thereof for spreading them to position said detent in locked engagement with a brake element lug, said member and one of said arms being provided with cooperating means for locking said member in its arms-spreading position.

4. A key for connecting a brake shoe to a brake head, comprising a pair of resilient arms connected to each other, and a strip-like wedge slidably mounted between said arms in engagement therewith for spreading them to locking position, said Wedge and one of said arms being provided with interengaging detents for locking said wedge in its arms-spreading position.

5. A key for connecting a brake shoe to a brake head, comprising a pair of resilient arms connected to each other, and a strip-like wedge slidably mounted between said arms in engagement therewith for spreading them to locking position, said wedge and one of said arms being provided with interengaging detents for locking said wedge in its arms-spreading position, the other of said arms being provided with a depression for receiw'ng the detents on the opposite arm whensaid wedge is withdrawn from its arms- Aspreading position.

6. A key for connecting a brake shoe to a brake head, comprising a pair of resilient arms connected to each other, and a strip-like wedge disposed between said arms in engagement therewith and slidable longitudinally thereof to spread them to looking position, and means for guiding said wedge in its longitudinal movement, said wedge and one of said arms being provided with interengaging detents for locking said wedge in its arms-spreading position.

v'7. A key for connecting a brake shoe to a brake head, comprising a pair of resilient arms connected to each other, and a strip-like wedge disposed between said arms in engagement therewith and slidable longitudinally thereof to spread them to locking position, said wedge and one ofsaid arms being provided with a cooperating and longitudinally extending rib and groove for guiding the wedge, and said wedge and one of said arms being provided with interengaging detents for locking said wedge in its arms-spreading position.

8. A key for connecting a brake shoe to a brake head, comprising a pair of arms connected to each other, a strip-like wedge slidably mounted between said arms in engagement therewith for spreadingthem to locking position, the inner end of said wedge being tapered to reduce the thickness thereof, and means for locking said wedge in its arms-spreading position.

9. A key for connecting a brake shoe to a brake head, comprising a pair of resilient arms connected to each other, and a strip-like wedge slidably mounted between said arms in engagement therewith for spreading them to locking position, said wedge and one of said arms being provided with interengaging detents for locking said wedge in its arms-spreading position, the 'lowermost of said detents on said arm being larger than the uppermost detent.

FREDERIC SCHAEFER. 

